The present invention relates to apparatus and method for completing high-pressure wells with large bore stingers while providing limited, controlled movement of the seals during large pressure, temperature and density changes.
One of the problems in completing high-pressure wells with a floating seal type completion is that the production tubing string can expand or contract and move under various well conditions. This movement can cause the tubing string to buckle and/or pull out of the seal receptable used in floating type completions. If the well is completed using a latch type completion to prevent movement, then certain conditions such as stimulating the well can cause the string to part as cooling and pressure attempt to contract the string. This invention overcomes the problem mentioned above by controlling movement of the production pipe string in high pressure wells in a manner that controls buckling and loads.
This completion technique also restricts movement of the seals during production of the well. Further, it provides for a back-up system in the event damage occurs within the lowermost polished bore receptacle or the seal section. In addition, the technique takes into account the possibility of the seals seizing within the polished bore receptacle. If the seal should seize in the down position during the production period, the completion design is such that shutting in of the well will not result in parting of the production tubing string. Also if damage should occur to the lowermost polished bore receptacle. The design allows for the use of a replacement section. This section is run on tubing and is located within the uppermost polished bore receptacle. Downward setting of weight forces slips to set on the inside diameter of the lowermost section of a larger diameter tieback string. The placement of this section provides a new polished/honed section above and within the lower section of the tieback which can then be used to once again accept the production tubing stinger and circulating string.
This method allows the limited controlled movement of sealed sections under extremely high pressure and high density changes in well completions. In addition, this completion procedure also prohibits movement of the critical sealing elements during production times and reduces seal wear during producing periods. The most important aspect of this completion is that use of this flexible system can reduce completion costs and provide a completion technique that allows the use of lower strength steels by allowing controlled movement of the strings to allow for drastic variations in pressures, temperatures and densities for deep hot wells.